This invention relates generally to systems for displaying pictorial representations to large numbers of people. More specifically, it relates to display systems capable of information from any one or more of a number of different sources and presenting the data in the form of alpha numerical information or pictorial representation.
In recent years there has been an ever increasing interest in means for displaying or exhibiting to large audiences information about or pictorial representations of different events. For instance, there has developed a desire for "scoreboards" in athletic stadia to present to the audience information about the game in progress, information about games in progress elsewhere and miscellaneous information about player performance, statistics and the like. The scoreboards having such capability are, of course, well known and in relatively common use around the country. However, it is believed that when such scoreboards are provided with the additional capability of producing moving pictorial representations, their utility is considerably enhanced. Even more than this, the ability of such a scoreboard to present to a large audience an "instant replay" of events in the game in progress, they serve a further purpose which the owners and operators of stadia athletic teams and advertisers find desirable.
In addition, the presence of a display device having the capabilities indicated above, affords the opportunity to present to large audiences a wide variety of graphic and pictorial material. For instance, it becomes possible to display animated cartoons of either a humorous or advertising nature. It also becomes possible to display pictorial information from the memory of large scale digital data processors.
It is believed that a scoreboard of the type suggested to be truly satisfactory, however, must be able to present pictorial displays in other than mere black and white. Otherwise, the delineation is not completely satisfactory and the image quality is not acceptable to most viewing audiences.
Therefore, this invention provides a display system wherein the image displayed is not merely a two tone image but one which is presented in what might be termed "shades of gray+, that is, there are gradations going from black to white.
Thus, it is an object of this invention to provide a novel large scale display system which produces almost instantaneous display of video signals ("instant replay") which, because it is capable of showing shades of gray, is very acceptable to viewing audiences.
The most common large scale display devices in use today use incandescent lamps arranged in a matrix and and connected so that individual lamps can be selectively excited to create the image whether that image be of alpha numerical characters or pictorial representations. This invention contemplates the inclusion of means which not only selectively excites the lamps in such a matrix but also controls their level of excitation so as to provide a range of light or brightness from full off to full on. In this manner, a pictorial representation appears as an image in which persons or other foreground images are clearly delineated from background and some of the subtleties of shadings can be seen.
One system, capable of producing a large scale display in a shades of gray format, is copending application Ser. No. 387,006, filed Sept. 28, 1973, assigned to the assignee of the present invention. That system, while quite satisfactory for producing a four shades of gray display, has been found to require extensive improvement when additional gradations in the level of display excitation are desired. Further, the copending application disclosed a system wherein the display board was non-synchronous.